Ask five sailors and you'll get six different opinions . . .
For whatever (little) it may be worth --
I change oil and filter on my Yanmar
every 100 hours (the genset, too). I have always changed oil and filter on my cars at 3000 miles. Diesels put a lot of cr*p into the lube oil and it cannot possibly hurt to change it more often than the 250 hours recommended by the manufacturer.
For a heavy over-the-road truck which is run a jillion miles a year, you might think hard about clever ways to extend, rather than shorten your oil change
interval. But our boat engines are rarely run for more than a few hundred hours a year, so why bother with anything other than frequent changes?
I run mine about 400 hours a year, so I am changing oil and filter roughly once a quarter. It's a simple job, costing little in the way of either money